1. Technical Field of the Invention
The present invention relates generally to the measurement field; and, more particularly, to a graphical indicator to facilitate adjusting the value of a parameter.
2. Description of Related Art
Many measurement applications require that the value of a parameter be adjusted from an initial value to a target value. Frequently, the adjustment process involves manipulating a physical or logical adjustment mechanism. For example, if the parameter is frequency, the adjustment process might involve turning a dial to change the frequency Similarly, if the parameter is signal strength, the adjustment process might require moving an antenna associated with a receiver to properly point toward a transmitter.
In many applications, the adjustment process is a multi-step adjustment process. More specifically, a value of the parameter is measured. If the measured value is different than the target value, the adjustment mechanism is manipulated to adjust the value of the parameter; and the adjusted value of the parameter is measured. If the adjusted value of the parameter is still different than the target value, the adjustment mechanism is again manipulated to further adjust the value of the parameter; and the new adjusted value of the parameter is measured. The process is repeated until the measured value of the parameter is the same as the target value.
A multi-step adjustment process as described above can be inconvenient and time-consuming as it may require the adjustment mechanism to be manipulated several times until the measured value of the parameter is the same as the target value.
In a multi-step adjustment process, an indicator is often utilized as a guidance tool to help a user home in on the target value. Depending on the parameter being adjusted, the indicator might be a meter, a thermometer, an audio signal generator, or another device that is capable of advising the user of the measured value of the parameter each time that it is adjusted. The indicator, in effect, provides feedback to the user as the value of the parameter is adjusted so that the user will know if the measured value of the parameter is approaching the target value and when the measured value reaches the target value.
Measurement software have also been developed to display a graphical indicator on a computer screen or other display device. Examples of graphical indicators include fill bars, color alarms and displays of various gauges. Such graphical indicators may include measurement span indicia that represents a span of parameter values capable of being represented by the indicator, target value indicia that represents the target value of the parameter, and measured value indicia that represents the most recent measured value of the parameter. As the value of the parameter is adjusted to approach the target value, the measured value indicia of the graphical indicator correspondingly moves to approach the target value indicia; and by viewing the graphical indicator, a user is provided with information regarding any further adjustment that may be required to reach the target value.
Known graphical indicators may comprise some combination of linear scale, logarithmic scale, graduated semi-circular scale, or the like; however, these options do not provide the user with a level of understanding of the relative separation between a measured value of a parameter and the target value that is needed for efficient manipulation of the adjustment mechanism. Specifically, in known graphical indicators, the sensitivity of the indicator is substantially the same throughout the measurement span of the indicator. This means that an amount of change in the measured value of the parameter is represented by a corresponding amount of movement of the measured value indicia that remains the same throughout the measurement span. In other words, the correspondence between the amount by which the measured value of the parameter changes and the amount of movement of the measured value indicia is linear throughout the measurement span. This linear correspondence throughout the measurement span makes it more difficult for a user to accurately adjust the value of the parameter to the target value, particularly when the measured value is near the target value, as the graphical indicator is simply not sufficiently precise to clearly indicate the amount of adjustment required to achieve the target value. Although the precision of the graphical indicator can be improved by increasing the scale of the indicator, this may result in the measurement span indicia being too large to properly fit within the display or it may require that the span of parameter values represented by the measurement span indicia be reduced.
In addition, in many measurement applications, the target value of a parameter may be a range of acceptable values rather than a single, discrete value; and known graphical indicators lack the capability of properly specifying and identifying a range of acceptable values.
In general, known graphical indicators are not fully effective in guiding a user in manipulating an adjustment mechanism so as to adjust the value of a parameter to a target value in an efficient manner.